Most of my friends in Merlin fandom are folks I've met through the multishipper comm camelot_fleet. It's a good place to hang out if you want to talk about problems with the show without running into a lot of character bashing, and there's more enthusiasm for poly ships and fanworks about The Ladies than in most other parts of the fandom. There's also a merlin_poly comm but that's fairly new and hasn't been too active so far.

I am in favor of Morgana-centric bizarro AUs! If you feel like reading one wouldn't interfere with your writing, I highly recommend netgirl_y2k's Pastimes and Lifestyles. If you'd rather hold off on reading that one, I also recommend everything else she's written.